2.0 Analysis 2.1 Introduction Based on a review of the aircraft's maintenance records and an examination of other available data, it is unlikely that a mechanical malfunction caused this accident. This conclusion is supported by recorded radar data regarding aircraft's speed, heading, and altitude, and by physical information from the accident site. The analysis of this accident will concentrate on safety issues related to deteriorating weather, an in-flight navigation error, flight below the minimum obstacle clearance altitudes, and a lack of terrain proximity warning equipment. 2.2 Environmental Conditions At the time the crew of RXX434 was completing their preflight planning, the ceiling and visibility at the departure airport of Vancouver, and the arrival airport of Victoria, met the VFR weather requirements although the overcast layer at 4000 feet agl would have obscured any available celestial illumination and reduced ambient lighting. The 0000 weather sequence and an amended terminal forecast for Victoria both indicated a lowering ceiling at the Victoria airport. However, because this information was issued after the crew's flight planning had been completed, it is unlikely that the crew were aware of these changes or would expect a ceiling to develop below their planned flight altitude of 2000 feet. Although updated weather and a PIREP were available by radio through the Vancouver FSS and the Area Control Centre, the crew of RXX434 did not contact these units to request the latest information. Other pilots, interviewed after the accident, indicated that they would rarely obtain these updates given the short duration of the trip and since they could normally see their destination shortly after take-off from Vancouver. The crew of RXX434 would have encountered the lower ceiling in the vicinity of Beaver Point. This lower layer of cloud would have restricted the pilot's view of the ground lighting and reduced the ambient lighting available to navigate by visual means. 2.3 Night Visual Navigation The crew of RXX434 had transmitted their intention to join left-base for runway 09. That transmission infers an intent to follow a route similar to the published Beaver Point arrival. As RXX434 passed Beaver Point, the aircraft track altered right toward high ground on the south-west end of Saltspring Island; a strong, low-level crosswind from the left might account for some of this divergence away from the intended track. Under normal conditions, a pilot will use ground lighting as a means of positional reference when operating at night. In this occurrence, the unexpected undercast layer at 1400 feet agl would have obscured the normal lighting references that delineate Satellite Channel. With these lighting references obscured, the only obstruction light the crew would be able to see would be the light mounted on top of Mount Tuam. Because of the effect of the low-level winds, that light would have been slightly to the left of the aircraft's track line and at a distance that was similar to the low-level light reference normally used. Under these conditions, it is likely that the lights seen by the crew would have appeared similar to those normally seen during a night visual approach into Victoria. The crew would have been unable to perceive the divergence of their aircraft's flight path away from the intended track by visual means. 2.4 Obstacle Clearance At night, VFR commercial operations must be conducted above a minimum obstacle clearance altitude. Although the COM did cite the applicable obstacle clearance requirements, it linked those requirements to night VFR flight in uncontrolled airspace. Given the way that the COM was written, it was possible to draw an incorrect inference that the minimum altitudes did not apply in controlled airspace. Two other recent TSB investigations (A97C0215 and A99P0006) identified similar issues in other COMs, as well as a lack of awareness by other companies and their flight crews of the night VFR obstacle clearance requirements. In addition, given that the company's crew manual suggested an en route altitude of 1500 feet for this particular flight, it is apparent that neither the company nor the crew involved was aware of the obstacle clearance requirements. The night VFR obstacle clearance requirements mitigate risk during the en route phase of flight. Had the crew been aware of the minimum altitudes, and had they respected them, the chance of a collision with terrain would have been eliminated. The night VFR obstacle clearance minimum altitudes do not provide protection during the approach or departure phases of night VFR flights. 2.5 Equipment Issues 2.5.1 Positive Navigation Guidance In this occurrence, the aircraft was not equipped with a GPS or other equivalent area navigation system that could provide positive tracking guidance to the pilot for the portion of the flight along the published VFR arrival route. Availability of a GPS system may have provided early indications to the crew of their deviation from the required track. However, conventional ground-based navigational aids were available to the pilot, but it could not be determined if the pilots were using these aids at the time of the occurrence. 2.5.2 Terrain Warning Equipment RXX434 was not equipped with a GPWS, which is designed specifically to warn of approach to terrain. Although such equipment is required on larger, passenger-carrying jet aircraft, that requirement does not extend to air taxi operations even though their operations are being conducted visually, at night, in high-risk mountainous areas, and often without the radar monitoring and support that is normally provided to larger, passenger-carrying jet aircraft. GPWS equipment is a recognized defence against controlled flight into terrain accidents and could be used to enhance safety in high-risk operational environments. With this type of equipment installed on the aircraft, the likelihood of this accident occurring would have been reduced. 3.0 Conclusions 3.1 Findings as to Causes and Contributing Factors Although weather information was available by radio from the Vancouver FSS specialists or from the Victoria Terminal controllers, there is no indication that the pilots requested weather updates from either of these units. The crew of RXX434 would have encountered the lower ceiling in the vicinity of Beaver Point. This lower layer of cloud would have restricted the crew's view of the ground lighting and reduced the ambient lighting available to navigate by visual means. With the loss of ground references, it is unlikely that the crew would have been able to perceive the divergence of the aircraft's flight path away from its intended track by visual means. The crew was unable to maintain separation between the aircraft and the terrain by visual means. The published VFR arrival and departure routes for Victoria were not consistent with obstacle clearance requirements for commercial operators. Regency Express Air Operations' crew manual suggested an en route altitude of 1 500 feet for this particular flight. That route and altitude combination is not consistent with published obstacle clearance requirements. 3.2 Other Findings At the time the crew completed their flight planning, the weather at the departure airport of Vancouver and the arrival airport of Victoria was suitable for a night VFR flight. An amended terminal forecast for Victoria indicating the presence of a temporary ceiling at 2000 feet asl was issued after the crew had completed their preflight planning activities. The regulation requiring GPWS equipment does not apply to air taxi operations because the aircraft used in those operations do not meet weight or propulsion criteria. 4.0 Safety Action 4.1 Action Taken 4.1.1 Notices to Airmen (NOTAMs) The TSB issued an occurrence bulletin to TC, NAV CANADA, and the management of Regency Express Air Operations which explained that the VFR arrival and departure procedures for Victoria may not be consistent with the obstacle clearance requirements. NAV CANADA subsequently issued a NOTAM (No. 990012) restricting the use of the published VFR arrivals into the Victoria airport during times when the tower was closed. This restriction has since been incorporated into the CFS. NAV CANADA issued a second NOTAM (No. 990013) restricting CARs Part VII operators from using the published arrival/departure procedures for Victoria at night. 4.1.2 TC Audit Following this accident, TC conducted a special purpose audit of Regency Express Air Operations. Areas of concern noted during that audit have been addressed and corrected by the company. 4.1.3 Commercial Air Service Standard--Night VFR Operations TC issued a Commercial and Business Aviation Advisory Circular (CBAAC No. 0153) on 12 March 1999 to draw air taxi operators' attention to the civil aviation regulation requiring increased obstacle clearance during night VFR operations. That advisory also highlighted the requirement for night VFR to be conducted along air routes or routes that had been specifically established by the air operator and designated in accordance with Commercial Air Service Standard (CASS) 723.34. CASS 723.105(1)(j) now requires COMs to include information and direction pertaining to night VFR operations. 4.1.4 Training Programs TC issued CBAAC Number 0161, dated 31 August 1999, detailing a new requirement for all CARs subpart-703 (Air Taxi), -704 (Commuter), and -705 (Airline) operators to undergo mandatory training for the avoidance of controlled flight into terrain accidents. 4.1.5 Company Crew Manual Regency Express Air Operations has removed any reference to recommended routes or altitudes from its crew manual. The company pilots have been briefed on the obstacle clearance requirements for night VFR flight in designated mountainous regions and have been informed that it is now the company's preferred practice to conduct these flights under instrument flight rules.